Process for the manufacture of phthalic anhydrid, phthalic acid, benzoic acid, and naphthaquinones.



San Francisco,

* invented a new and useful Process 30 sulfate and that naphtha 40frequentl I mixture, forcing the HARRY D. GIBBS, OF SAN FRANCISCO,CALIFORNIA,

AND COURTNEY CONOVER. or

PHILADELPHIA, PENNSYLVANIA.

PROCESS FOR THE MANUFACTURE OF P HTHALIC AN HYBRID,

PHTHALIC ACID, BEN ZOIC ACID, AND N APHTHAQUINON ES.

N 0 Drawing.

Specification of 146MB Patent. Patented Nov. 19, 1918. Application filedFebruary 17, 1917. Serial No. 149,361.

(DEDICATED TO THE PUBLIC.)

To all whom it may concern:

Be it known that we, HARRY D. GIBBS and COURTNEY CoNovEn, citizens ofthe United States of America, residing in the city of county of SanFrancisco, State of California, and in the city of Philadelphia, countyof Philadelphia, State of Pennsylvania, respectively, (whose ostofliceaddress is Washington, D. (1,2 ave 'or the Manufacture of PhthalicAnhydrid, Phthalic Acid, Benzoic Acid, and N aphthaquinones. Thisapplication is made under the act of March 3, 1883, chapter 143 (22Stat, 625), la and the invention herein described and claimed may beused by the Government of the United States or any of its ofiicers oremployees in prosecution of work for the Government, or any person inthe United States, without payment to us or any royalt ' gur inventionrelates to a process for the manufacture of phthalic anhydrid, phthalicacid, benzoic acid and naphthaquinones from 25 naphthalen It is wellknown that phthalic anhydrid and phthalic acid are commonly produced bythe oxidation of naphthalene by means of sulfuric acid in the presenceof mercury uinones are produced by the oxidation 0 naphthalene byvarious oxidizing agents in liquid form and that benzoic acid iscommonly produced from toluene. To manufacture phthalic anhydrid,phthalic acid, benzoic acid, and the methods commonly naphthaquinones byemployed in general requires the employment of costly oxidizingreagents. In addition products obtained by these methods are produced informs which make them di cult to separate and purify. The object of ourinvention is to provide a process for the manufacture of the materialsnamed which will be free from the objec- 46; tionable features of theprocesses employed at resent. V

ur invention consists in the production of phthalic anhydrid, phthalicacid, benzoic acid and napthaquinones from naphthalene 50 by heating thenaphthalene until it passes into the vapor phase, mixing thisnaphthalene vapor with anoxygen-containinggas mixture of gases intoclose contact with finely divided oxids of from 250 C. to 650 C., underwhich treat ment the naphthalene is oxidized to form the valuableproducts named, together with carbon dioxid and water.

The temperature and range of 250 to 650 C. is that range in which thereaction producing phthalic anhydrid progresses to a practical degree.The preferred temperature is between 350 and 550 (3., for the reasonthat the yield of phthalic anhydrid is greater at this range.

To illustrate the practical operation of our process we shall describein detail the preferred procedure. Naphthalene is melted and is causedto flow continuously at a measured rate into a heated chamber where itis volatilized. This vapor of na hthalene is then mixed with air inexcess 0 the proportion theoretically required to oxidize naphthalene tophthalic anhydrid, the mixture containing preferably at least four timesthe amount of air theoretically required. The mixture of air andnaphthalene vapor is passed into a reaction chamber maintained at atemperature ranging from 350 to 550 C., the preferred temperature being500 C. In this chamber the gas mixture is forced into. close contactwith oxids of vanadium in the form of a fine powder. This powder issupported on trays where by means of baflie plates, the current of mixedgases is forced through it. The gases are kept under pressureonlysuflicient to cause them to flow continuously throu h the reactionchamber. The roduets of t e reaction, consisting of pht alic anhydridand other oxidation products of na hthalene, are condensed, togetherwith unchanged naphthalene, by well-known processes. Phthalic anhydrid,together with small portions of other oxidation products, is separatedfrom the unchanged naphthalene by fractional sublimation.

We have discovered that the process as above described may be varied inmany ways and yet will produce one or all of the oxidation productsnamed. Thus, oxy en may be substituted wholly or in part or air, or airmay be mixed with .a gas which is relatively inert under the conditionsobtaining in the process. The oxids of vanadium may be mixed wiiii oiicr SHiDSiIIUQQES, sucis. as magnesium ouid, oikoiinc corih uuids othermciaiiic ouids osil-csios, OI iuci'i uiuccriois. The gas miuiuic may beiorougiii in couioci; with or forced through the coiuiysi iu mungdifici'eut ways. Tho proportioned uu giiiiiuions vapor to thooxygcu-couisiuiug gas mixtuic may be varied Within wide iimiis And tilereaction products may inc scpui'oicd by voi'ious-wcii-knowu moons Thusthc acid constituents may be dissolved in oikuiinc soiuiious andsubsequently freed from their suits icy the addition of suiiuiic orphosphoric acid and thou suioiiiucd. @T the reaction products may Too iicoicd "with ammonia gas or aqueous soiuiions 'oi ommouiu or i'uiiousmnii is *zo produce other uscfui mud vaiuubic compounds;

Having thus dcsciibsd our invention We ciuim- Ii. A process for themanufacture of phiiioiic auiiydrid, phtiiuiic acid, iosuzoic ucid anduopiiiiuiquiuoucs, which process cousisis iu suoicciiug uu oiiiiiuicucgusoous siccs u d iuixcd cuygoucontaining uiixouir "1c iiis u-c'iioudiiifczrmg iioui ills fractional su imiutiou mentioned ubovo.

i'uuudium oxids hsaicd to tciupcruiurss rungiugiii-om 350 io 55%?csniiguudc.

25.. A process fox the manufacture of 'piusimiic ouiuyduid, piotixsiicacid, ioenzoic acid and uupiiihuquiuouss, which process consists iusubjecting uuphtimicuc iii ti c

